This guide defines diffusion as the process by which a program or technique is transferred from the site where it was developed to another site. Effective diffusion is based on an understanding of how people and organizations can be helped to change as well as how programs are implemented. It is preceded by a carefully planned transition from operating the program to diffusing it. This guide is designed to assist educators responsible for diffusion to understand the diffusion process, to plan for initiating a diffusion project, and to assess needs for further work on the project's diffusion efforts. (Author/RE)